1. Field of the Invention
In co-pending application Ser. No. 099,676, there are described curable thiol-ene compositions using norbornenyl functional olefins. The invention of the present application pertains to silicone formulations utilizing particular norbornene functional silicone prepolymers which are cured by a thiol-ene or hydrosilation reaction mechanism.
2. Description of the Prior Art
In Petrov, et al, Zhurnal Obschei Khimii, 31, 1199 (1961), there is a description of the hydrosilation of various norbornene compounds, one of which is vinyl norbornene. The vinyl norbornene reaction was run a 30.degree. C. using trichlorosilane. The authors of this reference report that a mixture of products was obtained, the addition taking place at the both the internal double bond of the norbornene ring and at vinyl group in approximately similar proportions: ##STR2##
In various references, Watanabe et al, describe hydrosilation reactions of 5-ethylidenebicyclo (2,2,1)hept-2-ene: ##STR3## This hydrosilation is only reported to produce addition on the norbornene ring double bond. See for instance U.S. Pat. Nos. 4,599,440; 4,623,741; 4,625,043; and 4,640,968. These reaction products were used to make siloxane monomers for vulcanization to yield silicone elastomers.
From the Petrov et al and Watanabe et al, references persons skilled in the art would conclude that it is not possible to selectively hydrosilate norbornene derivatives containing other unsaturated sites because the norbornene unsaturation itself is reactive under hydrosilation conditions.